Electric meter.



C. F. KETTERING.

ELECTRIC METER. APPLICATION FILED MAY 29. N12

mmma Patented Sept. 21, 1915.

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CHARLES E. KETTERING, 0F DAYTON, OHIO, ASSIGNQR TO THE DAYTON ENGINEERING- LABORATORIES 00., A CORPORATION 05 OHIO. v

ELECTRIC METER.

To all whom it may concern .Be it known that 1, CHARLES F. Kn'rrnn ING, a citizen of the United States, residing at Dayton, county of Montgomery, and State of Ohio, have invented certain new and useful Improvements in Electric Meters, of which the following is a. full, clear, and exact description. f

This invention relates to an improvement in electrical measuring devices and is especia ly designed to provide a device or instrume at of thischaracter, wherein the various pal ts of the measuring device which are insulated or removed from the normal path or circuit of the electric current which is ada pted to pass through the meter, will be protected from the injurious and damaging effects of short or abnormal circuits which may be accidentally or inadvertently made or created through said parts, in a variety of ways. Further and incidental objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred embodiment of one form of the present invention is clearly illustrated.

Referring to the drawings, Figure 1 is a view in elevation of the electrical measuring device embodied in thepresent invention.

Fig. 2 is a diagrammatic view showing the electrical connections and devices included in the present invention- Referring to the drawing, the electrical measuring instrument disclosed in Fig. 1 is of that type known as an electrical mercury I meter, and of substantially thesame' type as that embodied in my co-pending application, filed April 17, 1911, Serial No. 621,512.

While the present invention is herewith shown and described as being combined with a specified type of meter, it should be understood that the invention is not limited in its application, to meters of this type alone, but that it may be combined with various types of meters or other electricalv measuring instruments.

It should be understood that in the following description and accompanying illustration, wherein the meter is described and shown as being interposed in an electric circuit, between a suitable cp rrent' generatei Specification of Letters Patent.

ed by said illustration and description, inas much as the present invention is applicable cation. This electric generating machine is placed in circuit with an accumulator or storage battery 22, by means of the wires 23 and 24. p

The line wire 24 is broken in order to allow the interposition of the meter 25, one portion of the wire 24 being connected'with the terminal 26 of the meter, while the other portion of the wire 24, is connected with the terminal 27 of the meter. These terminals 26 and 27 lead to the mercury chamber 28 of the meter .in the usual manner and are adapted to convey the current intothemercury chamber. This chamber is provided with a body of mercury which completes the circuit between the terminals 26 and 27. By having permanent magnets 29 arranged in .the bottom of said chamber and a soft iron ring 30, arranged in the top wall of the chamber, it will be seen that a magnetic field will be set up between the magnets and ring.

'From the above arrangement, i. e., the posithe mercury coming in contact with the armature, a coating of any suitable substance, which is not affected by mercury, is ap lied to the armature.

ere a large number of these meters or measuring devices are to be employed in any givensystem, it is desirable to have the p meters measure uniformly to somefpredetermmed standard, and inasmuch as there Patented Sept. 21, 1915.

Application filed May 29, 1912. Serial No. 700,487.

will be certain yerietiene in the elements be made for securing a substantially uniform measurement by the meter. In the I present instance, a variable shunt circuit 31,-

having a portion. thereof, of relatively high resistance, is secured to the terminals 26 and 27 and is adapted to shunt a certain predetermined amount of current about'the meter, from one portion of the wire 24:, to the other.

"This shunt circuit is made up of a pair of members 32 and 33, having an adjustable block or nut connection 34. A portion of the member 32, as at 35, is

made of higher resistance than the rcmain- -members 32 and 33, the

ing part of said member and the member 33, so that it will be seen, that by shifting the adjustable block or nut-34 laterally on, the

-- resistance of the shunt circuit may be increased or decreased as conditions Warrant. Referring to Figs, 1' and 2, the measuring.

device itself comprises a base plate-d0,

r is connected with the magnets in any suitable manner and supports-a1 thin metallic plate 42. See Fig. 2; This plate42 forms the bottom wall of the mercurychamber 28, wherein the armature iis, so positioned that it is free to rotate. The upper face of this plate is enameled to protect the same against amalgamation with the mercury. The spindle 4-5 carrying the armature 4A, is provided at its lower end with the bearing member 46, which fits in a socket 4:7, forme d in the plate 42, while at its upper end, this spindle is provided with a suitable gear wheel which meshes with one of the gear wheels of the gear train 50. The socket d7, formed in the plate 42, is free from enamel 'bility that an external shortcircuit will be or other insulation.

The gear train 50, mounted between the upper and lower train plates 51 and 52 respectively, is superposed upon a, block of insulation 54, which is so formed that when mounted upon the plate 42, the mercury chamber 28 is substantially inclosed.

Inthe testing of instruments of this character, and also in the assembling of instruments in electricalsystems of the character heretofore described, there is, always a liacreated between the upper or-expos'ed'train; plates and the oppositeline of the battery from that which passes through-the meterf" or between the said battery line and the magnets or conductive elements located, he:

bearing, it will result isa oat?- tions which-may be so displaced, as to cause external. short circuits, with the parts above .above named ways or in any other manner,

the current will pass through the bearing 46 of the spindle 45, or through the various pinions of the gear train 50, and as the amperage of the current will be much greater than the normal capacity of the spindle or in the burning out thereof.

Under certain circumstances, the various spindles and their bearings which are mounted between the upper and lower train plates of the meter, may be subjected to the same injurious efiects, as for instance, in cases where the supportingstuds 65, are made of insulating material, rather than from conductive material. Of course, it will be understood that when thestuds are constructed of conductive material, the capacity of said studs will prevent, as a general rule,-

any injury to the spindles and the bearings between the train plates 51 and 52.

The present invention is designed pri marily to take care of any undesirable external short circuits which may be created inany manner, between the various parts of the meter. This is accomplished by securing a suitable conducting element, such as for instance, a copper plate or wire 56, to the train plate '51 and the bracket 55, said bracket being in turn connectedto the magnets 29, as shown in dotted lines in Fig. 1.

Intermediate the ends of the said conducting element 56, one of the members of the shunt circuit 31 is connected in any suitablemanner, as for instance, by a soldered joint.

as shown at 57., in Fig. 2.

"With the application of the present invention, to meters of the type herein shown and 3 described, the course of the current, form ing an external short circuit between the up per or lower train plates and the line of the circuit designated by the numeral 23, will be as follows: from a given electrical source, such as the motor-generator 21, shown in Fig. 2, through .wire 23, thence through Whatever medium may be causing the short circuit, as shown in dct and dash line 61, in Fig. 2, through the protective conducting strip 56, thence through the shunt circuit 31, --into,the,other portion of the wire 24:, thus reventin an abnormal amount of current trompa-ssing through the spindle end bearingsofrthe various gear wheels of the gear train andthereby obviating all detrimental or injurieus efiects of the short circuit, on

the protected element.

low the mercury chamber of the meters-b1 "same action occurs when the short circuit is some external conductor. .For in sta;ice,th1s conductor may comprisevmerely an insttua ment wh .ch is used in theassembling' o hthe systems, or by, having supplemental sonnet? created Mtween the magnets or elements. loeated'b lowfthe mercury chamber otthe meter 'andjtilealine 23 of the main circuit,

ismewn bathe dot and dash line 62;

Substantially the Ms FD 1,154,02o i m that the current will ee the course of connecting said elements and the circuit least resistance, and pass through the conconnections. duc 'ng strip 56, into the shunt circuit 31 2. Inzan electrical measuring mstrument, and thence to the main line wire 24:, wherean electric circuit adapted to pass current b u sp ile Q5, of the armature and the through said instrument; elements formlng nd bearing thereof, will be protected parts of said instrument and conductively rom overload of electrical current. connected with said circuit; and a low re- As is shown in Fig, 2 of the drawings, the protective strip, or low resistance element 56, is connected with the shunt 31 at the point 57. It will therefore be seen that this is the same in efi'ect as though the strip 56 was connected directly with either the terminal 26 or the terminal 27.

Under certain conditions, as for instance, where the meter is used in portable electrical systems, the meter is liable to be tilted to such an angle that the mercury within the chamber 28, will flow to one side thereof, and thus open on break the circuit between the terminals 26 and27. Under these conditions, the shunt 31 is of especial value, inasmuch as the entire flow 'of current will be directed through the shunt 31, so that the mn'ning out of the meter will be prevented,

and also the main circuit of the electrical system will be maintained in closed condition. Now, if any short circuits are created, as has heretofore been explained, and the protective strip 56 is connected with the shunt 3i and to the conductive elements which are removed from the normal pathof the' -current, the current which will tend to flow through the short circuit, will be shunted through the protective strip 56 to the shunt 31 and thence through'its normal circuit, instead of through the armature spindle e5 or through he various pinions of the' g 50. In certain other systems, however, the employment of the shunt 31 becomes unnecessary and is entirely eliminated fromthe meter. Under these conditions, the protective strip .56 will be c'on-- nested directly with the terminals 26 or 27,

so that the pinions of the gear train 50, and

the armature spindle 45 will be protected from the effects of any short c1rcu1ts wh1ch are created in the manner heretofore set forth.

it will, of course, be understood that various changes mthe structure and application of the present invention, may be made to meet various conditions, and I reserve the right to make such changes and alteratlons,

as come within the scope of the present invention.

I claim is as follows:

1. In an electrical measuring instrument having circuit connections; a'no'rmal circuit for electrical current throu h the meassistance element connecting said parts with the circuit external to the measuring instrument.

3. In an electrical measuring instrument having an armature, the combination of auxiliary elements conductively connected to said armature; and' means for prevent ing injurious short-circuits from passing through said auxiliary elements when circuitsof this sort tend to pass through said elements.

4. Inan electric meter having an armature, circuit connections therewith; a shunt circuit external to said meter and connected with said circuit connections; auxiliary meter elements having conductive connection with said armature, and means connected with said elements and the shunt circuit,

whereby short-circuits tending to pass through said auxiliary elements will be shunted around said elements.

for preventing injurious short circuits through said gear train and said hearing when circuits of this sort tend to pass therethrough.

,6. In a' device of thecharacter described,

the combination with an electrical circuit; of anzelectrical measurmg mstrument 1nterposed in one line of said c1rcu1t, having conductive elements removed from the normal circuit of the current through the measuring instrument; and means for conductively connecting the -said elements with the line of the circuit in which the instrument is interposed, whereby short circuits which may be created between the conductive elements and the opposite-line of the circuit will be shunted around the conductive elements, to the line (if the circuit which includes the measuring instrument.

, 7. In an electrical system having circuit connections; a measuring instrument connected to one of said circuit connections and having portions thereof normally outside of said circuits but susceptible of being .short-circulted; and means for preventing injurious short-circuits through said parts when circuits of this sort tend to pass therethrouh, y

8. combination with an electrical measuring device" having a main circuit auxiliary elements.

therethrough; of a shunt circuit around said main circuit; conductive auxiliary elements of said meterremoved from said main circuit but conductively connected there with; and a permanent electrical connec' tion between said shunt circuit and said vent injurious short-circuits through said element.

10. In an electrical connections; a measuring instrument inter- Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

ystem having circuit posed in said circuit and having ingoing and outgoing terminals; auxiliary elements of said measuring device removed from said circuit but conductively connected therewith and permanent electrical 'conuectiens be tween said auxiliary elementsan'd one oi the terminals of themeasuring detdce whereby injurious short-circuits tendin to pass through said auxiliary elements will he shunted through said permanent electrical connections and around said elements.

In testimony ereof I afiix my signature in the presence of two subscribing witnesses. I

CHARLES F. KETTERING.

Witnesses:

WM. BOHLEBER, FELIX THoMAs.

Washinficn, I). G. 

